The present invention generally relates to magnetic recording mediums such as magnetic tapes and magnetic discs, and more particularly to a magnetic recording medium having a magnetic material thereof selected to a material which is suited for high density recording.
Conventionally, acicular ferromagnetic particles are generally used as magnetic particles which constitute a coated magnetic layer of a magnetic tape for recording and reproducing video signals thereon and therefrom. The acicular ferromagnetic particles are arranged in the longitudinal direction of a base film of the magnetic tape.
However, when the wavelength of a signal which is to be recorded is short, the conventional magnetic tape described above is disadvantageous in that the self-demagnetization effect of the recording magnetization is large and the reproduced output level decreases. The shorter the wavelength of the signal which is to be recorded becomes, the larger the self-demagnetization effect becomes and the more the reproduced output level decreases. Accordingly, the conventional magnetic tape is not suited for high density recording.
On the other hand, there is another conventional magnetic tape which is used in a vertical magnetic recording system which is intended for the high density recording. In this other conventional magnetic tape, hexagonal system ferrite magnetic particles are arranged with the c-axis thereof perpendicular to a surface of the base film. According to this magnetic tape, there is not much problem of the self-demagnetization even when the wavelength of the signal which is to be recorded is short. However, in the case where a ring magnetic head is used for the recording and reproduction of the signal, the magnetic field generated by the magnetic head in the longitudinal direction of the magnetic tape cannot be used effectively and the reproduced output level decreases. The decrease in the reproduced output level is considerably large especially with respect to a signal which has a long wavelength and is dominated by a component of the recording magnetization in the longitudinal direction of the magnetic tape. In addition, even with respect to a signal having a short wavelength, it is necessary to use a large recording current in order to obtain a large reproduced output level because the magnetic field generated by the magnetic head is smaller in the vertical direction compared to that in the longitudinal direction of the magnetic tape. As a result, the problem of saturation occurs and there is a disadvantage in that an accurate recording cannot be carried out.